Gamma-globulin injectable solutions containing sorbitol

ABSTRACT

An intravenously injectable solution of chemically unmodified γ-globulin having a complete molecular structure is disclosed, said solution containing sorbitol as a stabilizer and having a low electrical conductivity and a pH of about 5.5±0.2. The injectable solution does not cause an increase of γ-globulin polymer, a rise of anticomplement titer, or impairment of the activities of the γ-globulin, either during preservation or upon administration to a living body.

FIELD OF THE INVENTION

This invention relates to a solution of chemically unmodified completemolecular type γ-globulin which can be administered intravenously.

BACKGROUND OF THE INVENTION

Preparations of chemically unmodified immunoglobulin which constituteplasma protein, and particularly preparations containing IgG as a mainingredient have been widely used for treatment and prophylaxis ofvarious infectious diseases. Since γ-globulin is readily polymerized ina dissolved state which causes side effects when administeredintravenously, it has hitherto been formulated into freeze-driedpreparations. The freeze-drying method is also believed to be the bestform for storing the γ-globulin from the standpoint of lability ofchemically unmodified γ-globulin having a complete molecular structurewhen dissolved. Accordingly, the importance of freeze-drying isgenerally recognized.

On the other hand, liquid preparations are advantageous over thefreeze-dried preparations due to convenience of administration becauseliquid preparations are free of the need to be dissolved, for example,in injectable distilled water on use. However, the above-mentionedlability of γ-globuloin has retarded the practical application of liquidpreparations of γ-globlulin.

A γ-globulin liquid composition having a pH of from about 3.5 to 5 andan ionic strength of less than about 0.001 has recently been proposed asa stable liquid preparation as disclosed in U.S. Pat. No. 4,396,608 orEuropean Patent Publication No. 73371A. However, such a strongly acidicliquid preparation is not always favorable when administered to a livingbody because the γ-globulin is liable to aggregate (i.e., to polymerize)in body fluids maintained substantially neutral due to the bufferingcapacity of such body fluids.

SUMMARY OF THE INVENTION

One object of this invention is to provide an intravenously injectablesolution of chemically unmodified complete molecular type γ-globulinwhich does not cause an increase of γ-globulin polymer, a rise ofanticomplement titer, or impairment of the activities of the γ-globulin,either during preservation or upon administration to a living body.

The above object of this invention can be accomplished by anintravenously injectable solution which comprises a low-conductivesolution containing chemically unmodified complete molecular typeγ-globulin, said solution further containing sorbitol and having a pH ofabout 5.5±0.2.

DETAILED DESCRIPTION OF THE INVENTION

The terminology "chemically unmodified complete molecular typeγ-globulin" as used herein means γ-globulin possessing the followingproperties:

(a) It remains intact without undergoing any modification or change.Therefore, it does not contain γ-globulin fragments, such as Fab,F(ab')₂, Fc, etc.

(b) It shows neither reduction of antibody titer nor antibody spectrumas compared with intact γ-globulin.

(c) Its anticomplementary activity (complement fixation activity) issufficiently lower than 20 units (CH₅₀) which is regarded safe based onJapan Biological Preparation Standard according to Notification No. 159(October 1985) issued by Ministry of Public Welfare of Japan. (One unitin terms of CH₅₀ is defined as the amount of complement necessary tohemolyze half the amount of 5×10⁸ cells of sensitized erythrocyte in 7.5ml of a reaction mixture having a certain ionic strength and pH value,and a certain amount of Ca⁺⁺ and Mg⁺⁺ under the reaction of 60 minutesat 37° C.)

(d) It contains more than 95% by weight of the γ-globulin monomer basedon the total weight of the γ-globulin.

The process for obtaining the chemically unmodified complete moleculartype γ-globulin which can be used in the present invention is notrestricted as long as intact γ-globulin having a low anticomplementtiter can be obtained. The most efficient process comprises treatingγ-globulin for intramuscular injection, which can be prepared usingpre-existing facilities and has already been employed as a biological,with an acid and separating the resulting agglomerate. Putting aside thequestion as to complexity of processes involved and reduction in yield,it would be preferable to use γ-globulin having a low anticomplementtiter which is obtained by treating γ-globulin with a nonionic surfaceactive agent to remove γ-globulin agglomerates causative of complementfixation.

Typical processes for preparing the chemically unmodified completemolecular type γ-globulin will be described below.

Starting Material:

A fraction containing immunoglubulin is used as a starting material.This fraction is not particularly limited in so far as it originatesfrom human serum and contains an immunoglobulin fraction. Specificexamples of such an immunoglobulin-containing fraction include FractionII+III and Fraction II obtainable by ethanol fractionation of Cohn (E.J. Cohn et al., J. Am. Chem. Soc., 68, 459 (1946)), and pastes ofimmunoglobulin-containing fractions equivalent thereto. The startingmaterial may contain impurities, such as human blood-group antibodies,kallikrein, prekallikrein, IgM, IgG polymers, etc. (1) PolyethyleneGlycol (PEG) Treatment:

The starting γ-globulin-containing fraction is terated with a lowconcentration of PEG, and the supernatant liquor is recovered.

The starting material is first suspended in an appropriate aqueoussolvent. The aqueous solvent may contain sodium chloride, sodiumphosphate, potassium phosphate, acetic acid, sodium acetate, citricacid, sodium citrate, etc.

The resulting suspention is treated with PEG having a molecular weightof from about 1,000 to 10,000, and preferably from about 2,000 to 6,000.The treatment can be carried out, for example, by mixing the suspensionand PEG while stirring, usually at a temperature of from 0 to 4° C. fora period of from 30 minutes to 6 hours. Recommended treatment conditionsare: a protein concentration of from 1 to 20 w/v %, and preferably from5 to 15 w/v %; a PEG concentration of from 4 to 10 w/v %, and preferablyfrom 4 to 8 w/v %; a pH of from 4 to 6 and preferably from 4.5 to 5.5;and an ionic strength of from 0.0001 to 0.1 M, and preferably from0.0001 to 0.01 M.

The mixture is then subjected, for example, to centrifugation at 6,000to 8,000 rpm for 10 to 30 minutes to recover the supernatant liquor.

The supernatant liquor thus separated is then treated with a highconcentration PEG, and a precipitate is recovered as follows.

he supernatant liquor is treated with PEG having a molecular weight offrom 1,000 to 10,000, and preferably from 2,000 to 6,000. The treatmentcan be carried out, for example, by mixing the supernatant liquor andPEG at 0° to 4° C. for 30 minutes to 6 hours. Recommended conditions forthe treatment are: a protein concentration of from 1 to 20 w/v %, andpreferably from 5 to 15 w/v %; a PEG concentration of from 10 to 15 w/v%, and preferably from about 11 to 13 w/v %; a pH of from 6 to 9, andpreferably from 7.5 to 8.5; and an ionic strength of from 0.0001 to 0.1M, and preferably from 0.0001 to 0.01 M.

The mixture is then subjected, for example, to centrifugation at 6,000to 8,000 rpm for 10 to 30 minutes to recover the precipitate. (2) AnionExchange Treatment:

This process comprises dissolving a γ-globulin-containing fraction in anaqueous solvent and contacting the solution with an anion exchanger torecover the non-adsorbed fraction. The treatment with an anion exchangeris particularly effective to remove IgM or IgG polymers.

The anion exchenger to be used comprises anion exchanging groups bondedto an insoluble carrier. The anion exchanging groups includediethylaminoehtyl (DEAE) , a quaternary aminoehtyl (QAE) groups, etc.,and the insoluble carrier includes agarose, cellulose, dextran,polyacrylamide, etc.

A γ-globulin-containing precipitate is dissolved in an appropriateaqueous solvent having a pH of from 5 to 8 and a low ionic strength, andpreferably an ionic strength of from 0.0001 to 0.1 M. The aqueoussolvent may contain the solutes as described in Process 1) above. Theprotein concentration of the resulting solution preferably ranges from 1to 15 w/v %, and more preferably from 3 to 10 w/v %.

The γ-globulin solution is then contacted with an anion exchangerequilibrated with the same aqueous solvent as used above, either in abatch system or in a continuous system. For instance, batchwisetreatment can be carried out by mixing the γ-globulin solution with ananion exchanger in an amount of from about 10 to 100 ml per ml of theanion exchanger, stirring the mixture at 0° to 4° C. for about 0.5 to 2hours, and centrifuging the mixture at 6,000 to 8,000 rpm for 10 to 30minutes to recover the supernatant liquor. Continuous treatment can beeffected by passing the γ-globulin solution through a column of an anionexchanger at a rate of from about 10 to 100 ml per ml of the anionexchanger and recovering the non-adsorbed fraction.

(3) Treatment with Fixed Diamino Compound:

This process comprises contacting a γ-globulin-containing fraction witha fixed diamino compound and recovering a non-adsorbed fraction. Thetreatment with a fixed diamino compound is particularly effective toremove prekallikrein or kallikrein.

The fixed diamino compound to be used is a diamino compound fixed to aninsoluble carrier. The diamino compound includes aminobenzamidine,aminobenzguanidine, lysine, arginine, etc., and the insoluble carrierincludes agarose, cellulose, dextran, silica gel, glass, etc.

Fixation of the diamino compound to the insoluble carrier can beeffected by any known technique. For example, the diamino compound canbe fixed to agarose, cellulose, or the like carrier by a CNBr activationmethod (Axen, R. et al., Nature, 214, 1302 (1967)); or to silica gel,glass or the like carrier by an oxirane method (Cuatreasas, P. et al.,Biochemistry, 11, 2291 (1972)).

A γ-globulin-containing fraction is contacted with the fixed diaminocompound under conditions of from 1 to 5 w/v %, and preferably from 3 to10 w/v %, in protein concentration; from 5 to 8, and preferably from 6to 7, in pH; and from 0.0001 to 0.1 M, and preferably from 0.0001 to0.01 M, in ionic strength, either in a batch system or in a continuoussystem.

For example, in a batch system, from about 10 to 100 ml of the fractionis mixed with 1 ml of the fixed diamino compound, and the mixture isstirred at 0` to 10° C., and preferably 0° to 4° C., for 0.5 to 4 hours,and preferably about 40 minutes to 2 hours, followed by centrifugationat 6,000 to 8,000 rpm for 10 to 30 minutes to recover the supernatantliquor.

In a continuous system, the fraction is passed through a column of thefixed diamino compound in an amount of from anout 10 to 100 ml per ml ofthe fixed diamino compound, and the non-adsorbed fraction is recovered.

(4)Treatment with Fixed Human Blood-Group Substance:

This process comprises contacting a γ-globulin-containing fraction witha fixed human blood-group substance to recover a non-adsorbved fraction,and is particularly suited for removal of human blood-group antibodies.

The fixed human blood-group substance to be used is a human blood-groupsubstance fixed to an insoluble carrier. The human blood-group substancecan be prepared by any known technique. For example, erythrocytes ofhuman blood-groups A, B, AB, or O are subjected to hemolysis in ahypotonic solution or ultrasonic treatment and then purified by ammoniumsulfate fractionation or PEG fractionation.

The thus prepared human blood-group substance is dissolved inphysiological saline and heat-treated at temperatures effective forinactivation of viruses present, e.g., between about 50° and 70° C., andpreferably about 60° C., for 7 to 13 hours, and preferably about 10hours, or between about 80° and 130° C., and preferably between about95° and about 121° C., for about 1 to 40 minutes, and preferably 2 to 30minutes. Thereafter, the solution is centrifuged to remove any insolublematter. The supernatant liquor is then subjected to dialysis againstdistilled water to obtain a human blood-group A, B, AB, or O substance,respectively.

The insoluble carrier to which the human blood-group susbtance is fixedincludes agarose, cellulose, dixtran, silica gel, glass, etc.

Fixation can be carried out in a known manner. For example, the humanblood-group substance can be fixed to agarose, cellulose or the likecarrier by a CNBr activation method or to silica gel, glass or the likecarrier by an oxirane method.

A γ-globulin-containing fraction is contacted with the fixed humanblood-group substance having been equilibrated with the above-describedaqueous solvent under conditions of a protein concentration ranging from1 to 15 w/v %, and preferably from 3 to 10 w/v %, a pH of from 5 to 8,and preferably of from 6 to 7, and an ionic concentration ranging from0.0001 to 0.1 M, and preferably from 0.0001 to 0.01 M, either in a batchsystem or in a continuous system.

For example, in a batch system, the γ-globulin-containing fraction ismixed with the fixed human blood-group substance in an amount of fromabout 10 to 100 ml per ml of the fixed human blood-group substance, andthe mixture is stirred at 0° to 10° C., and preferably 0° to 4° C., for30 minutes to 4 hours, and preferably about 30 minutes to 2 hours,followed by centrifugation at 6,000 to 8,000 rpm for 10 to 30 minutes torecover the supernatant liquor.

In a continuous system, about 10 to 100 ml of the fraction is passedthrough a column of 1 ml of the fixed human blood-group substance, andthe non-adsorbed fraction is recovered.

(5) Heat Treatment:

According to this process, a γ-globulin-containing fraction is heated inthe presence of a stabilizer under such conditions that impurities,e.g., HB virus, AIDS virus, etc., are compretely inactivated whileminimizing reduction of antibody activities of immunoglobulin. The heattreatment is carried out in a dry state having a water content of 3% orless (i.e., dry heat treatment) or in a dissolved state in the form ofan aqueous solution (i.e., wet heat treatment).

The stabilizer which can be used in either the dry or wet heat treatmentpreferably includes disaccharides (e.g., sucrose, maltose, etc.) andsuger alcohols (e.g., sorbitol, mannitol, etc.).

A recommended amount of the stabilizer to be added is from 0.5 to 5 w/v%, and preferably from 1 to 3 w/v %, in the dry heat treatment, or 10w/v % or more, and preferably from 10 to 50 w/v %, in the wet heattreatment.

It is desireble that the protein concentraiton of theγ-globulin-containing fraction to be heat-treated be adjusted to between1 and 10 w/v %, and preferably to between 3 and 7 w/v %, for the dryheat treatment, or to between 0.1 to 30 w/v %, and preferably to between5 and 20 w/v %, for the wet heat treatment.

In the case of the dry heat treatment, after a stabilizer is added tothe γ-globulin fraction, if desired, followed by sterilization byfiltration, the water content of the fraction is adjusted to 3% or less,and preferably 1% or less by, for example, freeze-drying. Freeze-dryingcan be carried out, for example, at a temperature of from 20° to 40° C.for a period of from about 24 to 96 hours in vacuo of 0.5 mmHg. Then,the fraction is heated at a temperature of from 50° to 70° C., andpreferably at about 60° C., for a period of from 10 to 200 hours, andpreferably of from about 50 to 100 hours. Stability of theimmunoglobulin during the heating can be ensured by conducting the heattreatment in an inert gas atmosphere, such as nitrogen, argon, helium,etc.

In the case of the wet heat treatment, after the aqueous solution of theY-globulin-containing fraction is adjusted to a pH of from 4.5 to 6.5,and preferably from 5 to 6, the solution is heated at 50° to 70° C., andpreferably about 60° C., for 10 minutes to 20 hours, and preferablyabout 10 hours.

Preparation and purification of the γ-globulin to be used in the presentinvention can be achieved by appropriately combining the above-descirbedprocesses according to the purpose. In a prefered embodiment thestarting material is subjected to wet hear treatment, PEG teratment,blood-group substance treatment, and anion exchange treatment in thisorder.

The thus prepared chemically unmodified complete molecular typeγ-globulin is dissolved in water in a usual manner to prepare andaqueous solution in concentrations ranging from 1 to 10 w/v %, andpreferably from 3 to 7 w/v %. Sorbitol is then added thereto inconcentrations of from 1 to 10 w/v %, and preferably from 2 to 10 w/v %,and the solution is adjusted so as to have a pH of 5.5±0.2, andpreferably about 5.5, and a low electrical conductivity, and preferablynot more tha 1 mmho, and more preferably not more than 0.6 mmho. Theresulting solution is further subjected to working-up procedurescommonly employed in the art, such as sterilization by filtration,pouring into vials, and the like, to obtain intravenously injectableliquid preparations of chemically unmodified complete molecular typeγ-globulin.

Throughout the above-described processes, a pH value of a reactionmixture is adjusted using 0.5 N NaOH or 0.5 N HCl, and electricalconductivity is measured at 8° C. with a conductivity measuringapparatus.

Dose of the γ-globulin of the present invention for intravenousinjection is the same as a conventional intravenously injectableγ-globulin, i.e., about 500 to 5,000 mg.

The chemically unmodified complete molecular type γ-globulin liquidpreparations according to the preset invention undergo neither anincrease of γ-globulin polymers nor a rise of anticomplement titereither during long-term preservation or upon administration to a livingbody, and satisfactorily retain their appearance and properties whenpreserved for a long time.

The present invention is now illustrated in greater detail by way ofTest Examples and an Example. In the test examples, testing methods wereas follows.

(1) Appearance:

Turbidity of the liquid preparation that is of interest in connectionwith appearnce, was visually observed and rated as follows:

A: No abnormality (clear and cololess)

B: Slightly colored or turbid

C: Seriously colored or turbid

Further, an absorbance at 600 nm was measured to evaluate appearance.

(2) Determination of Polymer Content:

The content of γ-globulin polymers based on the total weight ofγ-globulin in the liquid preparation was determined by means of highperformance liquid chromatography.

(3) Anticomplement Titer:

Merasured in accordance with Capat and Mayer, ExperimentalImmunochemistry, 225 (1961) and Nishioka & Okada, Men-eki no Seikaoaku(Biochemistry in Immunology), Vol. 103, Kyoritsu Shuppan (1971). Thatis, a sample was added to 100 units of complement, and the decrease inunits of the complement was measured and taken as the anticomplementtiter.

(4) Measles Antibody Titer:

Measured in accordance with the hemagglutination inhibition test method(Rosen, L., Virology, 13, 139 (1961)), and expressed by an internationalunit (IU/100 mg).

Each chemically unmodified complete molecular type γ-globulin-containingcomposition prepared in the following test examples was heat-treated at56° C. for 60 minutes and the stability of the composition wasevaluated. In Test examples and Example, distilled water was used as asolvent. A pH value of the preparation was adjusted using 0.5 N NaOH or0.5 N HCl and electrical conductivity was measured with a conductivitymeasuring apparatus, CD-35MII model (M & S Instrument Co.).

TEST EXAMPLE 1

A liquid composition of chemically unmodified complete molecular typeγ-globulin having a γ-glubulin concentration of 5 w/v %, an electricalconductivity of 1 mmho (measured at 8? C.), and a pH of 5.5 wasprepared. Each of stabilizers shown in Table 1 below was added to aconcentration of 5 w/v %, and the resulting liquid preparation wastested. The results obtained are shown in Table 1.

                  TABLE 1                                                         ______________________________________                                                                          Polymer                                                             Absorbance                                                                              Content                                     Stabilizer Appearance   at 600 nm (wt %)                                      ______________________________________                                        Glucose    C            --        --                                          Galactose  C            --        --                                          Sucrose    A            0.013     28.62                                       Lactose    C            --        --                                          Maltose    C            --        --                                          Sorbitol   A            0.015     4.58                                        Mannitol   B            0.024     --                                          Albumin    C            --        --                                          None (heated)                                                                            C            --        --                                          None (non- A            0.004     0.00                                        heated)                                                                       ______________________________________                                    

It can be seen from Table 1 that addition of sorbitol achievedsatisfactory results.

TEST EXAMPLE 2

A liquid composition of chemically unmodified complete molecular typeγ-globulin having γ-globulin concentration of 5 w/v %, an electricalconductivity of 1 mmho (measured at 8° C.), and a varied pH value asshown in Table 2 below and containing 5 w/v % of sorbitol or sucrose asstabilizer was prepared. The test results are shown in Table 2.

                  TABLE 2                                                         ______________________________________                                               Sorbitol       Sucrose                                                                     Polymer           Polymer                                                     Content           Content                                 pH       Appearance (wt %)    Appearance                                                                            (wt %)                                  ______________________________________                                        3.5      A          >10       A       >10                                     4.0      A          >10       A       >10                                     4.5      A          >10       A       >10                                     5.0      A          5.38      --      >10                                     5.5      A          4.24      A       >10                                     5.5      A          0.00      A       0.00                                     (non-heated)                                                                 6.0      A          5.28      A       >10                                     7.0      B          --        B       --                                      8.0      C          --        C       --                                      9.0      B          --        B       --                                      10.0     A          >10       A       >10                                     ______________________________________                                    

As is apparent from Table 2, γ-globulin is particularly stable at a pHof around 5.5 in the presence of sorbitol.

TEST EXAMPLE 3

A liquid composition of chemically unmodified complete molecular typeγ-globulin having a γ-globulin concentration of 5 w/v %, a sorbitorlconcentration of 5 w/v %, a pH of 5.5, and a varied electricalconductivity (measured at 8° C.) as shown in Table 3 below was prepared.Test results are shown in Table 3.

                  TABLE 3                                                         ______________________________________                                        Electrical                Polymer                                             Conductivity              Content                                             (mmho)         Appearance (wt %)                                              ______________________________________                                        0.5            A          0.00                                                 (non-heated)                                                                 0.5            A          4.20                                                1              A          7.10                                                2              C          --                                                  5              C          --                                                  10             C          --                                                  ______________________________________                                    

It can be seen that γ-globulin shows particular stability when thepreparation had an electrical conductivity of 1 mmho or less.

TEST EXAMPLE 4

A liquid preparation of chemically unmodified complete molecular typeγ-globulin having a γ-globulin concentration of 5 w/v %, an electricalconductivity of 0.5. mmho (measured at 8° C.), a pH of 5.5, and a variedsorbitol concentration as shown in Table 4 was prepared. The testresults obtained are shown in Table 4.

                  TABLE 4                                                         ______________________________________                                        Sorbitol                  Polymer                                             Concentration             Content                                             (w/v %)        Appearance (wt %)                                              ______________________________________                                        0              C          --                                                  1              C          --                                                  2              A          12.24                                               5              A          4.06                                                8              A          3.29                                                10             A          2.34                                                15             A          0.10                                                20             A          0.03                                                ______________________________________                                    

As can be seen from Table 4, stability of γ-globulin increases with thesorbitol concentration.

TEST EXAMPLE 5

A chemically unmodified complete molecular type γ-globulin liquidcomposition having a γ-globulin concentration of 5 w/v %, a sorbitolconcentration of 5 w/v % (for rendering the composition physiologicallyisotonic), a pH of 5.5 and an electrical conductivity of 0.5 mmho(measured at 8° C.) was prepared. The composition was found to be clearand colorless and to have a polymer content of 0.00 wt %, ananticomplement titer (CH₅₀ /ml) of 8, and a measles antibody titer (IU)of 32.

The preservation stability of the composition was evaluated in terms ofappearance, polymer content, anticomplement titer, and a measlesantibody titer, and the results obtained are shown in Table 5.

                                      TABLE 5                                     __________________________________________________________________________    Temper-                             Anticomplement Titer                                                                        Measles Antibody Titer      ature Appearance     Polymer Content (wt %)                                                                       (CH.sub.50 /ml)                                                                             (IU)                        (°C.)                                                                        1 Mth.                                                                             3 Mths.                                                                            6 Mths.                                                                            1 Mth.                                                                             3 Mths.                                                                            6 Mths.                                                                            1 Mth.                                                                             3 Mths.                                                                           6 Mths.                                                                            1 Mth.                                                                            3                                                                                  6                  __________________________________________________________________________                                                               Mths.              11    colorless                                                                          colorless                                                                          colorless                                                                          0.00 0.02 0.01 7    9   9    32  32   32                       clear                                                                              clear                                                                              clear                                                         25    colorless                                                                          colorless                                                                          colorless                                                                          0.00 0.02 0.03 8    8   10   32  32   32                       clear                                                                              clear                                                                              clear                                                         37    colorless                                                                          colorless                                                                          colorless                                                                          0.02 0.08 0.14 12   16  22   32  32   32                       clear                                                                              clear                                                                              clear                                                         __________________________________________________________________________

EXAMPLE 1

In 10 liters of distilled water was suspended 1 Kg of a Cohn fractionII+III paste. After adjusting to a pH of 5.5, the suspension wassubjected to centrifugation. The supernatant liquor was recovered, and50 g of sorbitol was added thereto per 100 ml so as to have a finalconcentration of 33 w/v %, followd by heating at 60° C. for 10 hours.After the heat treatment, the mixture was adjusted to a pH of 5.5, andPEG #4000 was added thereto so as to have a final concentration of 6 w/v%, followed by centrifugation at 2° C.

The recovered supernatant liquor was adjusted to a pH of 8.0 with a 1Nsodium hydroxide aqueous solution. PEG #4000 was again added thereto toa final concentration of 12 w/v %, followed by centrifugation to obtainan IgG fraction as a precipitate.

The resulting fraction was dissolved in water, and 100 ml of the IgGsolution was passed through a column packed with 3 ml of humanblood-group substance fixed to Formyl Cellulofine® (Seikagaku Kogyo Co.,Ltd.) having been equilibrated with distilled water to thereby adsorbhuman blood antibodies thereto. By this adsorption treatment, theblood-group antibody titer decreased from (1:32) to (1:2).

To the resulting solution was added 1 ml of DEAE-Sephadex® per 50 ml ofthe solution, and the mixture was stirred at 0° to 4° C. for about 1hour, followed by centrifugation at 7,000 rpm for about 20 minutes torecover an IgG solution as a supernatant.

The resulting IgG solution was diluted with distilled water so as tohave an IgG concentration of 5 w/v %. After adjusting to a pH of about5.5 with a sodium acetate aqueous solution, sorbitol was added theretoto a final concentration of 5 w/v %. The resulting aqueous solution wasfound to have an electrical conductivity of about 1 mmho. The solutionwas sterilized by filteration to obtain an intravenously injectablesolution of immunoglobulin.

While the present invention has been described in detail and withreference to specific embodiments thereof, it will be apparent to oneskilled in the art that various changes and modifications can be madetherein without departing from the spirit and scope thereof.

What is claimed is:
 1. An intravenously injectable solution ofchemically unmodified gamma-globulin having a complete molecularstructure, said solution containing sorbitol in a concentration of from1 to 20% by weight per volume as a stabilizer and having a lowelectrical conductivity and a pH of about 5.5±0.2, said solution havingan electrical conductivity of not higher than 1 mmho as measured at 8°C.
 2. An intravenously injectable solution as claimed in claim 1,wherein more than 95% by weight of said γ-globulin is γ-globulinmonomer.
 3. An intravenously injectable solution as claimed in claim 1,wherein said solution has an electrical conductivity of not higher than0.6 mmho as measured at 8° C.
 4. An intravenously injectable solution asclaimed in claim 1, wherein said sorbitol is present in a concentrationof from 2 to 10% by weight per volume.
 5. An intravenously injectablesolution as claimed in claim 1, wherein said solution has a pH of about5.5.